I remember thinking, when I first read this back in July, that it doesn't help matters because the writer appears to have misunderstood the timeline, particularly where he states that Baldur's Gate: Descent into Avernus "takes place about 100 years before Baldur’s Gate 3 even begins."

Unless BG3 really does take place in the 1590s DR, I think it's safe to assume that BG: DIA does not take place 100 years before BG3 but rather that BG: DIA and BG3 take place 100 years after BG1 and 2.